This invention relates to composite tabbed shingles including an improved underlying backer strip having an extended nailing area for more secure attachment of the shingle unit to a roof deck.
A major impediment to permanent shingle placement resides in the failure of attachment to the roof deck. Commercially, the attachment of shingle units to a deck is accomplished with a hand held nailing gun which rapidly ejects nails for penetration through the shingle membrane and underlaying substrate. However, because of the limited area of markings, the rapid feed of nails from the nail gun and the need for precise positioning of the gun over the nail line markings, many of the attachment sites are missed so that the nail passes above the area where the backer underlays the headlap and engages only the headlap portion of the multi-membrane shingle to the roof deck. This results in excessive stress at the point of nail penetration and eventual displacement of the shingle unit.
One solution to this problem suggests the substitution of a backer strip having the same width as the top sheet. However, this solution is found to be impractical since the weight of the unit is greatly increased causing problems in packaging, handling and installation. Additionally, many more nails are required to carry the weight of the shingle.
Accordingly it is an object of this invention to overcome the above problems and avoid single membrane misses causing shingle displacement by means of a commercially feasible improvement in the configuration of the backer strip.
Another object is to provide component portions of a composite tabbed shingle including the improved backer strip which can be produced in a single, economical cutting operation.
Still another object is to provide a shingle with a wider area of attachment sites which eliminates the need for precise placement of nails in order to penetrate all of the shingle membranes without materially adding to the weight of the unit.
Yet another object is to provide a nailing area which accommodates a variety of nailing patterns and which may conserve the number of nails required for secure and permanent shingle attachment.
Another object is to provide shingle units which are conveniently packaged in a nesting position with regard to the laminated backer strips.
These and other objects and advantages will become apparent from the following description and disclosure.
In a tabbed composite roofing shingle, the present invention concerns an improved underlying backer strip having a plurality of spaced, vertically extending projections along its top margin to provide a significantly wider nailing area for engaging and attaching all components of a laminated composite shingle to a roof deck.